Re: [APML] 500mm mirror lens as a guidescope?

[George Anderson <georgea@cam.org>]

Hi Chris

The lens is purely a camera lens and not a scope/camera lens.  The QC is
contained in a box with a Pentax lens mount and the mirror lens will
attach to the camera using the Pentax bayonet fitting. The primary
mirror is solidly bonded to the back and the focus works by extending
the barrel (thus the corrector and secondary) and not by shifting the
primary (ala SCT). I am not photographing through the mirror lens.
I'll report the results to the list after I run a cheap roll of film
through to check the tracking and stability of the focusing over time.

George Anderson
Montreal Canada

Clear skies and good health

Christopher Go wrote:
> 
> I have one of these scopes and I would definitely NOT use it as a
> guidescope. Mirror shift of this scope is crazy!  Even at prime
> focus!  Your better off getting a refractor from Apogee with focus lock and
> guide rings attached to the scope for the mounting rings.
> 
> I tried even to use this scope piggybacked a years ago.  It couldn't keep
> focus particularly at the Zenith!
> 
> Regards,
> 
> Chris
> 
> At 10:57 PM 9/2/03 -0400, you wrote:
> >While messing around with getting my B&W quickcam autoguider working and
> >starting to worry about focuser flexure on my el-cheepo guidescope I
> >started wondering (dangerous habit)...
> >For widefield shots with a 35mm camera (50mm lens or less) would a
> >guidescope with a 500mm focal length be sufficient?
> >The 500mm f/8 mirror lens I have is very lightweight and has no
> >detectable barrel flexure. The effective aperture is only 62mm but that
> >is only a touch smaller than my 70mm f/10 scope that I use for manual
> >guiding.
> >Any thoughts from those in the know?
> >
> >George Anderson
> >Montreal Canada
> >
> >Clear skies and good health
> >_______________________________________________
> >Astro-Photo mailing list
> >Astro-Photo@seds.org
> >http://seds.org/mailman/listinfo/astro-photo
> 
> Christopher and Vicky Go
> Christone Industries
> Manufacturer and Exporter of Quality Fossil Stone and Wrought Iron Furniture
> Cebu, Philippines
> http://www.christone.net
> astropage: http://astro.christone.net
> 
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo